Download 2. Functional anatomy of the pelvic floor and lower

Functional anatomy
of the female pelvic floor
and lower urinary tract
Stefano Floris, MD, PhD
Department of Obstetrics and Gynaecology
Ospedale San Giovanni di Dio, Gorizia, Italy
ANATOMY
URINARY CONTINENCE
FUNCTION
PELVIC ORGAN
SUPPORT
Pelvic floor composition
peritoneum
viscera
endopelvic
fascia
levator ani
muscles
perineal
membrane
external genital
muscles
Key structures
-Endopelvic Fascia
Key considerations
-Overall structure and
function of pelvic floor
-Pelvic Diaphragm
-Urogenital Diaphragm
-Obturator foramen
-The vaginal-uterine
axis
-Circumferential
support of vagina and
uterus
-Sacrospinous ligament
-Urethra
-Anterior vaginal and
urethral support
Pelvic Bones 3-D
Pubic symphysis
Sacrum
Pelvic Bones 3-D
Oerlich 1983
Pelvic Bones
Pubocoxygeal muscle
Ileocoxygeal muscle
“Bone” Ligaments
Pelvic floor supports
pubic symphysis
urethra
pubourethral lig.
vagina
&
uterus
cardinal
lig.
rectum
uterosacral lig.
sacrum
Viscero-fascial layer
- Combination of pelvic viscera and endopelvic fascia
- Attaches and suspends the pelvic organs to the
pelvis wall (Ricci and Thom 1954; Ulhenhuts and Nolley 1957; De Lancey 1992)
- Continous sheet-like mesentery
- Parametrium and paracolpium
- “Ligaments” and “fascia”: supportive structures
with prominent blood vessels, nerves and fibrous
tissue
Viscero-fascial layer
support
lateral
fusion
I
Level
Level
II
Levator
ani
12
NORMAL VAGINAL AXIS AND THREE LEVELS OF SUPPORT OF UTERUS AND VAGINA
Normal vaginal axis (axes!!)
Possible defects in POP
urethra
anterior
vaginal
wall
Lateral defect
Transverse defect
vaginal vault
posterior
vaginal
wall
Central defect
anus
Pelvic Organ Prolapse
2D Pelvic Floor Muscles - superior view
The pelvic floor muscles
The puborectalis muscle (inferior fibres of pubococcygeus)
The puborectalis muscle
Muscular components of pubococcygeus muscle
• Large diameter slow twitch type I fibers
predominant- provide static visceral support
• Fast twitch type II fibers- assists in active
closure of pelvic visceral organs
• 40% of women have lost function or
coordination of this muscle
3-D Pelvic Floor Muscles - superior view
Pelvic Floor Muscles - 3D lateral and posterior view
Anatomic variations of the pelvic floor nerves adjacent to
the sacrospinous ligament
Levator ani nerve
Takeyama et al. Int Urogynecol J 2008
Levator ani nerve and the inserted mesh
The levator ani nerve forms a common
trunk with pelvic splanchnic nerve and
crosses the inside of sacrospinous
ligament, whereas the pudendal nerve
runs to the outside of the sacrospinous
ligament
Takeyama et al. Int Urogynecol J 2008
Pelvic Floor Muscles
Obturator muscle
Innervation of the levator ani muscles
Grigorescu et al. Int Urogynecol J 2008
Sacrospinous ligament and coccygeal muscle
Coccygeal muscle
Oerlich 1983
Perineal membrane and external genital muscles
3-D Superficial
muscular layer
2-D Superficial
muscular layer
ischiocavernosus
bulbospongiosus
Trasverse superficial
perineal muscle
Obturator nerve and artery
(internal view)
Obturator nerve
Striated urogenital sphincter muscle
DeLancey 2003
Urethral and para-urethral muscles
Oerlich
Oerlich1983
1983
Topography of urethral and para-urethral structures
APPROXIMATE
LOCATION (%)
REGION OF
URETHRA
PARA-URETHRAL
STRUCTURES
URETHRAL LUMEN TRAVERSES
THE BLADDER WALL
0-20
INTRAMURAL
20-60
MID-URETHRA SPHINCTER URETHRAE MUSCLE
PUBOVESICAL MUSCLE
VAGINO-LEVATOR ATTACHMENT
60-80
PERINEAL
MEMBRANE
COMPRESSOR URETHRAE MUSCLE
URETHROVAGINAL SPHINCTER
MUSCLE
80-100
DISTAL
URETHRA
BULBOCAVERNOSUS MUSCLE
DeLancey JOL Obstet Gynecol1986
PREMENOPAUSE
From Hollihn KU, 1997
POSTMENOPAUSE
Ultrasound in urogynaecology
Urethral lumen
Circular striated
muscle
Urethral mucosa
Lower Urinary Tract Innervation
Pelvic Nerve
(Parasympathetic)
ACh
+M3
- β3
Hypogastric Nerve
(Sympathetic)
NE
+α
α1
+N
Pudendal Nerve
(Somatic)
ACh
Bladder filling and urine storage require:
•Accomodation of increasing volumes of urine
at a low intravesical pressure and with appropriate
sensation
• A bladder outlet that is closed at rest and remains so
during increases in intraabdominal pressure
•Absence of involuntary bladder contractions (detrusor
overactivity or hyperreflexia)
Bladder emptying requires
•A coordinated contraction by the bladder smooth
musculature of adequate magnitude and duration
• Concomitant lowering of resistance at the level of the
smooth sphincter and of the striated sphincter
•Absence of anatomic obstruction
Role of Norepinephrine and Serotonin
Depression-Pain Perception
• Dysregulation of
NE and 5-HT is
strongly
associated
with depression1
NE and 5-HT also
modulate pain
sensitivity through
their presence in the
descending pain
pathway2,3
1. Fields H. Neuropsychiatry Neuropsychol Behav Neurol. 1991;4(1):83-92.
2. Verma S, Gallagher RM. Int Rev Psychiatry. 2000;12(2):103-114.
3. Blier P, Abbott FV. J Psychiatry Neurosci. 2001;26(1):37-43.
4. Thor KB, Katofiasc MA. J Pharmacol Exp Ther. 1995;274(2):1014-1024.
•
NE and 5-HT play a
central role in lower
urinary tract function4
NeuroUrology
Serotonin and norepinephrine are involved in
the functioning of the lower urinary tract
Stress Urinary
Incontinence (SUI)
Sacral spinal cord
Smooth bladder muscle
Serotonin and norepinephrine work
centrally and play key
roles in lower urinary tract
function including contraction of
the striated urethral sphincter1
Urge Urinary
Incontinence2
Pudendal Nerve
Anticholinergic agents work
peripherally on the bladder
to treat urge urinary
incontinence/OAB2
Striated urethral sphincter muscle
1. deGroat WC. Basic neurophysiology and neuropharmacology. In: Abrams P, et al, eds. Incontinence. Health Publishing Ltd.; 1999:105-154.
2. Kreder D, et al. Eur Urol. 2002;41:588-595.
Space of Retzius (drawn from cadaver dissection)
DeLancey JOL 1989
Space of Retzius (photo of cadaver dissection)
Ashton-Miller et al. Scand J Urol Nephrol Suppl. 2005
Relationship of the supportive tissues of the urethra
DeLancey JOL. Neurourol Urodyn 1989
Urethropelvic ligament
P
U
Pubourethral
urethropelvic
PUBOURETHRAL LIGAMENT
Pubis
P
U
Pubourethral
bladder
THE HAMMOCK HYPOTHESIS
DeLancey JOL. Am J Obstet Gynecol 1994
Thanks
for your
attention!